AVS 45th International Symposium
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThM

Paper PS-ThM9
Modeling of IMP Copper for Electroplating Seed Layer Application

Thursday, November 5, 1998, 11:00 am, Room 318/319/320

Session: Plasma Applications in Copper Metallization
Presenter: H.M. Zhang, Applied Materials
Authors: H.M. Zhang, Applied Materials
I. Hashim, Applied Materials
P.J. Ding, Applied Materials
B. Chin, Applied Materials
J.C. Forster, Applied Materials
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Copper is being considered for semiconductor metallization because of its better conductivity, and higher electromigration resistance compared to aluminum. Current trends suggest that electroplating will be the primary choice for copper deposition in sub-0.25 µm generations because of its relatively low cost, high deposition rates, and ease of filling high aspect ratio features. However a conducting seed layer is required prior to electroplating. Ion-metal-plasma (IMP) deposition of copper has been demonstrated to provide a good seed layer for aspect ratios up to 4.5 :1.@footnote 1@ To meet the challenges of filling even higher aspect ratio features, a better understanding of both the electroplating and IMP process is required. In this paper, we will focus on extending the limits of the IMP copper deposition process by using simulations. A 2-dimensional hybrid plasma equipment model (HPEM ),@footnote 2@ developed at the University of Illinois, is used to model the IMP Cu system. Simulation results of the deposition rate show good agreement with experimental data. The ionization ratio of copper can be increased by increasing the RF power or the process pressure. TEM analysis of IMP copper deposition into high aspect ratio features show a significant improvement of the step coverage at higher pressures. A good correlation was obtained between ionization fraction predicted by simulation and experimentally obtained bottom coverage measurements. This study will show that with proper optimization, the application of IMP Cu to the deposition of seed layers for electroplating can be extended to future generation and geometries. @FootnoteText@ @footnote 1@I. Hashim et al, Abstract submitted for VLSI Multilevel Interconnection Conference, 1998. @footnote 2@M. Grapperhaus and M.J. Kushner, J. Applied Physics., 81, 569 (1997)